public class test04 {
    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     *     int val;
     *     TreeNode left;
     *     TreeNode right;
     *     TreeNode() {}
     *     TreeNode(int val) { this.val = val; }
     *     TreeNode(int val, TreeNode left, TreeNode right) {
     *         this.val = val;
     *         this.left = left;
     *         this.right = right;
     *     }
     * }
     */
        public TreeNode deleteNode(TreeNode root, int key) {
            if(root==null){
                return root;
            }
            //找到了
            if(root.val==key){
                if(root.left==null){
                    return root.right;
                }else if(root.right==null){
                    return root.left;
                }
                //左右子树均不为空
                //左子树放在右子树最左
                TreeNode cur = root.right;
                while(cur.left!=null){
                    cur = cur.left;
                }
                cur.left = root.left;
                return root.right;
            }
            //利用递归继续找
            if(root.val>key){
                root.left = deleteNode(root.left,key);
            }else if(root.val<key){
                root.right = deleteNode(root.right,key);
            }
            return root;
        }
}
